
function Food(ele){
    this.ele=ele

    this.len=20
    this.foodObj= null
    this.foodX=0
    this.foodY=0
}

Food.prototype.create=function(){
    let divObj=document.createElement('div')

    divObj.style.width=this.len+'px'
    divObj.style.height=this.len+'px'
    divObj.style.background='green'
    divObj.style.position='absolute'

    this.foodObj=divObj

    this.ele.appendChild(divObj)

    this.move()
}

Food.prototype.move=function(){
    let foodXMaxNum=this.ele.clientWidth/this.len-1
    let foodYMaxNum=this.ele.clientHeight/this.len-1
    
    this.foodX=Math.floor(Math.random()*(foodXMaxNum-0+1)+0)*this.len 
    this.foodY=Math.floor(Math.random()*(foodYMaxNum-0+1)+0)*this.len 

    this.foodObj.style.left=this.foodX+'px'
    this.foodObj.style.top=this.foodY+'px'
}








